The communication industry mainly relies on use of electromagnetic waves for detection, positioning, communications and the like. The electromagnetic waves can be separated, converged, deflected and diverged by different materials or devices. Materials capable of deflecting an electromagnetic wave (i.e., changing a propagating direction of the electromagnetic wave) are mainly inhomogenous materials; that is, inhomogeneity of the materials leads to unbalance in distribution of the refractive indices. Specifically, differences in densities or species of materials can all lead to variations of the refractive indices.
Prior art inhomogenous materials for deflecting an electromagnetic wave are usually formed by laminating multiple layers of materials having different refractive indices together. According to such properties as the frequency and the wavelength of the electromagnetic wave to be deflected, a refractive index distribution of the inhomogeneous material can be designed, and then appropriate materials having corresponding refractive indices can be chosen in individual distribution regions.
This kind of material for deflecting an electromagnetic wave is disadvantageous in that, the refractive indices of currently available materials are inherent and cannot be designed arbitrarily. If refractive indices in some regions of the desired refractive index distribution cannot be obtained from natural materials currently available, the inhomogenous material as a whole will fail to satisfy the desired deflecting requirements.
Metamaterials refer to man-made composite structures or composite materials having supernormal physical properties that natural materials lack. Through structurally ordered design of critical physical dimensions of the materials, restrictions of some apparent natural laws can be overcome to obtain supernormal material functions that natural materials lack.
For conventional metamaterials, dielectric constants and magnetic permeabilities thereof at different points are changed primarily by periodically arranging different man-made metal microstructures on a substrate. However, arranging the man-made metal microstructures on the metamaterial substrate is not the sole way of changing the dielectric constants and the magnetic permeabilities of different points of the metamaterials to achieve different functions, and arranging the man-made metal microstructures on the metamaterial substrate requires use of a complex process, which is difficult to be implemented.